|Similar Eucalyptus triflora, Eucalyptus cretata, Eucalyptus doratoxylon, Eucalyptus brownii, Eucalyptus notabilis|
Eucalyptus dura, also known as the smooth-branched ironbark, or gum-topped ironbark, is a Eucalyptus tree of eastern Australia. It is a relatively uncommon tree found on dry ridges and mountainous regions of north-east New South Wales and south-east Queensland, particularly around the McPherson Range and peaks such as Mount Greville.
A medium-sized tree, it can grow to 15 metres (50 ft) tall. Major trunks have a dark, hard bark that is furrowed. In contrast, smaller branches near the top of the canopy have smooth white bark (hence the names "smooth-branched" and "gum-topped"). Leaves are alternate, concolorous (same colour in each side) or slightly discolorous and semi-glossy. The leaves range in size from 15 to 30 millimetres (0.6 to 1.2 in) long. The woody fruits are 7–10 mm (0.28–0.39 in) long.
The leaves of E. dura are rich in oils, particularly β-phellandrene and 1,8-cineole. These oils may be suitable for development of a bacteriostat.